そらきた！

Hi,
I'm a little confused by this expression I found in "Harry Potter and the Philosopher's Stone". The full sentence, along with the original English, is as follows.

そらきた。お望みどおりだ。マルフォイの目の前で箒に乗って、物笑いの種になるのさ。
Typical. Just what I always wanted. To make a fool of myself on a broomstick in front of Malfoy.

The sentence is quite clear, except for the very first part: そらきた. I couldn't find this expression on my dictionaries nor online (except as part of the name of a regional delicacy, with a nice backstory). I did find the slightly different but very plausible "それきた" on the Kojien, with the following definition:

予測通りに事が起きた場合や物の受け渡しの場合に発する掛け声｡

Which should mean something along the lines of "An exclamation used when something happens according to estimations, or when you pass on/deliver something." Given my not-so-great knowledge of Japanese, my translation of the definition could be wrong. But if it is right, it does seem to fit.

My question is: am I right in thinking that, そら being a colloquialism for それ（は）, the two expressions are one and the same? If not, what exactly does そらきた mean?